1. FIELD OF THE INVENTION
This invention relates to 5-, 6-, 7- or 8-(2-hydroxy- 3-alkylamino)propoxycarbostyrils useful as .beta.-adrenergic blocking agents and a process for preparing the same.
2. DESCRIPTION OF THE PRIOR ART
It is well known that certain carbostyril derivatives exhibit useful pharmaceutical activities. Representative compounds of this type have been disclosed in Journal of Medical Chemistry, Vol. 15, No. 3, pp 260-266 (1972), Japanese Patent Publication No. 38789/1971, and Chemical Abstracts, 62, 1b 212e (1965), etc. However, these prior art references do not teach that the compounds having a (2-hydroxy-3-alkylamino)propoxy group at 5-, 6-, 7- or 8-position of a carbostyril moiety possess an excellent .beta.-adrenergic blocking activity.
The present inventors have found that novel 3,4-dihydrocarbostyril derivatives having a 3-substituted-aminopropoxy group at 5-, 6-, 7- or 8-position of the carbostyril moiety possess a useful .beta.-adrenergic blocking activity as described in our copending application Ser. No. 325,981 filed on Jan. 23, 1973.
As a result of further investigation on other derivatives, it was unexpectedly found that compounds having a (2-hydroxy-3-alkylamino)propoxy group at 5-, 6-, 7- or 8-position of the carbostyril moiety exhibit the above pharmacological activity and that these compounds can easily be prepared from the corresponding 5-, 6-, 7- or 8-(2,3-epoxy)propoxycarbostyril or 5-, 6-, 7- or 8-(2-hydroxy- 3-halo)propoxycarbostyril or a mixture thereof, retaining the .beta.-adrenergic blocking pharmacological activity.